Fluid hoist



Aug. 3 1926.

J. P. HEIL ET AL FLUID HOIS'I Filed Dec. 19, 1924 3 Sheets-Sheet 1 INVENTORS.

:3 .T KIIT 3/} TORNEYS.

Aug. 3 1926. 1,594,728

J P. HEEL-ET AL FLUID HOIST Filed Dec. 19, 1924 5 Sheets-Sheet 2 ATTORNEYS Aug. 3 1926. 1,594,728

J. P. HEIL ET AL FLUID HOIST Filed Dec. 19. 1 3 Sheets-Sheet 5 A TTORNEYS.

Patented Aug. 3, 1926..

UNITED STATES PATENT OFFICE.

JULIUS I. HEIL AND CHARLES G. EISENBERG, JR., 0F MILWAUKEE, AND' GEORGE L. LANDRY, OF WEST ALLIS, WISCONSIN, ASSIGNORS TO THE HEIL 00., OF MILWAU KEE, WISCONSIN, A CORPORATION OF WISCONSIN.

FLUID HOIS'I'.

Application filed December 19,- 1924. Serial No. 757,078.

This invention relates to improvements in fluid hoists.

Fluid hoists as now manufactured are provided with independent reservoirs for holding the at times surplus amount of oil required in operating the hoist due to the oil displaced by the piston rods when within the cylinders. These reservoirs are usually formed of sheet metal and are placed above and to one side of the cylinders. Trucks provided with hoists are subjected to rough usage with the result that often the reservoirs are injured and leak or the connections between the cylinders and the reservoir leak and there is not suflicient oil left to move the pistons.

It is one of the objects of the present invention to overcome the before mentioned objectionable features and provide a fluid hoist in which provision is made within the cylinders for taking care of the at times ex cess oil.

A further object of the invention is to provide a fluid hoist which is adapted to automatically stop when the pistons reach their uppermost position.

A further object of the invention is to provide a fluid hoist having means for bypassing the oil from one side of the pistons to the other to permit the pistons to initially move downwardly.

A further object of the invention is to pro-- vide a fluid hoist which is of simple construction, is strong and durable and is well adapted for the purpose described.

With the above and other objects in view the invention consists of the improved fluid hoist and its parts and combinations as set forth in the claims, and all equivalents thereof.

In the accompanyingdrawin'gs in which the same reference characters indicate the same parts in all of the views:

Fig. 1 is a side view of a motor truck provided with the improved fluid hoist, parts broken away to show other parts in the rear thereof, the view also illustrating by dotted lines the body portion of the truck in its upper position line 2-2 of Fig. 1 and on a larger scale;

Fig. 3 is .a vertical sectional view of one 1g. 2 is a vertical sectional view taken on Fig. 4 is a central sectional detail view taken on line 4-4 of Fig. 2; and

Fig. 5 is a sectional detail view taken on line 5-5 of Fig. 2.

Referring to the drawings the numeral 8 indicates a portion of a motor truck, 9 the side members of the chassis or frame, 10 the cab or seat portion and 11 the tiltable load carrying body of the truck. Said body near its rear end portion is pivotally connected to tltie pgpposite side members 9 by pivot bracke s The improved fluid hoist 13 comprises a pair of spaced cylinders 14 connected together at their lower ends by a lower tie bar 15. The outer upper portions of the cylinders are provided with outwardly projecting portions 16 having alined trunnion recesses or sockets 17 for receiving the in wardly projecting trunnions 18 of the trunnion brackets 19 which rest on and are bolted to the side members 9 of the chassis. The

cylinders are pivotally supported on said trunnions and depend downwardly there from and are provided with pistons 20 reciprocally positioned therein. The pistons are mounted on the lower end portions of piston rods 21 which extend upwardly through the upper closed ends of the cylinders and the stuffing nuts 22 and are provided with upper eyed ends 23. Said eyed ends are pivotally connected to the truck body beneath the bottom portion by a pivot rod 24 which extends transversely of said bottom portion and is mounted in brackets 25 connected to the side members 9. Said pivotal connections permit the piston rods and cylinders to tilt and aline with said 'pivotal connections while the truck body is traveling its arc of movement to unloading position.

I The cylinders are formed with lower ports 26 and upper ports 27 whichrespectively charge or dischargethe fluid medium from the cylinders below or above the pistons. The ports 26 are in communication with ducts 28 which are formed in the walls of the cylinders and lead upwardly from said ports 26. to alower connecting and trans- 1 versely extending pressure duct 29 formed in the conduit member 30. .The upper ports '27- of the cylinders. are of less height than the heightv te s and. a e ls n a fiow of the fluid medium therethrough.

This valve is turned to open communication between the by-pass ducts 29 and 32 when it is desired to lower the truck body.

A rotary gear pump 36 mounted on the conduit member 30 is positioned between the ducts 29 and 32 and is connected respectively to said ducts by inlet and outlet pump ports- 37 and 38. The lower port 38 is provided with a spring actuated ball check valve-38' opening outwardly from the pump. One of the gears of the pump is connected to and driven by the transmission 39 by a connecting rod or shaft 40 and the transmission of power to the pump connecting rod is controlled by a controlling rod 41 and a lever 42. The plug valve 34 is also controlled by a rod 43 and a lever 44, both levers 42 and 44 being preferably located within the cab or adjacent the seat of the truck.

As considerable more space within the cylinders is required to accommodate the piston rods when they are in their inner position than when in their outer position and to supply the varying amounts the upper portions of the cylinders are formed with integral chambers 45 which comprise enlargements of the cylinders and are open to the bores thereof the full diameter of said bores. chambers are also in communication with the annular ducts 31 by means of the vertical ducts 46 which extend from said annular ducts upwardly into the chambers 45. Ball valves 47 are positioned in the ducts 46 which are arranged to permit the upward flow of fluid through the ducts 46 but prevent the downward flow thereof. The fluid medium flows from the chambers 45 through the' ports 27 and the annular ducts 31 and then through the ducts to the plug valve and the pump and plug valve to the cylinders beneath the pistons. From the pump to the lower portionsof the cylinders the fluid is under pressure from the pump to force the pistons upwardly.

When the pistons are in their upper position they cover the ports 27 so that to per-' mit the initial downward movement of the pistons, the ports 46 before mentioned, are provided to permit the fluid beneath the pistons to flow upwardly intothe chambers 45 and above the pistons until the pistons uncover'the ports 27 and when soun o el'ed Said the fluid will flow therethrough and above the pistons and into the chambers 45.

The upper portions of the cylinders are connected together by a vent tube 48 which is curved upwardly and at its highest point is provided with a vent opening 49 to permitthe entrance and escape of air to and from the chambers 45 of the cylinders.

In use the fluid hoist ismounted on a motor truck in the manner shown in Fig.

1 and when it is desired to dump the contents of the truck body the transmission controlling rod is operated to transmit motion from the transmission to the pump and the operation of the pump will draw the fluid medium from above the pistons and force it into the cylinders below the pistons and raise said pistons. The upward movement of the pistons will tilt the truck body connected thereto and when the pistons have closed theupper ports 27 and thus automatically closed the supply of fluid medium or oil to the pump, the pump may continue to operate but as its supply of oil is cut off, it cannot pump any more into the cylinders below the pistons and therefore the further upward movement of the pistons will automatically stop. This feature is very desirablein constructions of this kind as it eliminates any danger of damage to the hoist in the event that the operator inadvertently neglects to stop the operation of the pump.

The pistons will remain in their upper position whether or not the pump is in operation.

lf it is now desired to lower the truck body the valve rod 43 .is operated to open the valve 34 and when opened the oil in the cylinders will 'flow through the valve and the annular ducts 31 and upwardly through-theports 46 until the pistons uncover the ports 27 and when uncovered the oil will flow directly through the ports '27 and into the cylinders above the pistons, and when the excess oil is forced out of the cylinders below the pistons it will fill the cylinders above the pistons and overflow into the chambers forming part of the cylinders. The speed of lowering the truck body is controlled by opening or closing more or less of the port of the valve.

It is to be understood that one or any number of cylinders and pistons may be used without departing from the spirit and scope ing the opposite end ports together, a valve and a pump intersectin the duct between the ports for moving a uid medium within the cylinder from one side of the piston to the other to move the piston to predetermined positions of rest and for moving the overflow fluid medium into the storage chamber of the cylinder, one of said positions of rest of the piston closing one of the ports and thereby automatically stopping the movement of the piston, and a duct provided with a check valve interposed between and connecting the cylinder port to the chamber and having a check valve to permit the initial movement of the piston when it is covering said cylinder port.

2. A fluid hoist, comprising a vertical cylinder having ports at its upper and lower end portions and a storage chamber at its upper end portion, a piston within the cylinder and between the ports and having a piston rod extendin upwardly through the upper portion of t e cylinder, ducts connecting the opposite end ports together, a valve and a pump intersecting the duct between the ports for moving a fluid medium within the cylinder from one side of the piston to the other to move the piston to predetermined positions of rest and for moving the overflow fluid medium into the storage chamber of the cylinder, the upper position of rest of the piston closing the upper port and thereby automatically stopping the upward movement of said piston, and a duct interposed between and connecting the upper port to the'storage chamber and having a check valve to permit the initial downward movement of the piston when it is covering said cylinder port.

3. A fluid hoist, comprising a pair of vertical cylinders having ports at their upper and lower end portions and storage chambers formed at their upper end portions, pistons within the cylinders and between the ports of the respective cylinders and having piston rods which extend upwardly through the cylinders, ducts connecting the ports of the cylinders together in pairs, a pump intersecting the pairs of ducts between the res ective ports thereof for moving a fluid me ium within the cylinders from one side of the pistons to the other to move the pistons to predetermined positions of rest, the piston in the upper of said ositions of rest closing the upper ports an thereby automovement of the matically stopping their upward movement, a valve controlling the passage of" the fluid medium from one side of the istons to the other without passing throug the pump, and ducts connecting the upper ports to the storage chamber and having check valves permitting only the upward flow of the fluid medium from the ducts to which the upper ports are connected to permit the initial downward movement of the pistons, said storage chambers receiving the excess fluid medium when the pistons are moving downwardly to their lower positions.

4. A fluid hoist, comprising a pair of cylinders having ports at their upper and lower ends and storage chambers formed at their upper end portions, encircling ducts formed at the upper end portions of the cylinders with which the upper ports are in communi cation, pistons within the cylinders and between t e ports of the respective cylinders and having piston rods which extend upwardly through.the cylinders, said pistons having upper and lower positions of rest, ducts connected to the lower ports and to the encircling ducts, the pistons in their upper positions of rest closing the upper ports and thereby automatically stopping their upward movement, a valve controlling the passage of the fluid medium from one side of the pistons to the other, a pump intersecting the ducts between the lower ports and the encircling ducts, and check valved ducts connecting the encircling ducts to the storage chambers to permit the upward flow of the fluid medium and the initial downward pistons, said storage chambers receiving the cylinders when the pistons are moving downwardly to their lower position.

the excess fluid medium from 5. A cylinder for a fluid hoist having ports in its upper and lower portions and a storage chamber formed at its upper end, an annular duct connected to the upper port, a duct connecting the lower port to the annular duct, a duct connecting the annular duct to the storage chamber, and a check valve controlling the duct connected to the storage chamber. 4

In testimony whereof, we afiix our signatures.

JULIUS P. HEIL. CHARLES G. EISENBERG, JR. GEORGE L. LANDRY. 

